After the SHTF, there are going to be many challenges. Our generation has been rather spoiled with easy access to clean water and modern medicines that help fight infections. After a major disaster, clean water will be extremely limited, sanitation systems will be down, and waste disposal companies will be closed.

That means there’s going to be a lot of garbage, which attracts all kinds of critters. Without a functioning sewage system and garbage pickup, human waste and trash will pile up fast, spreading diseases. And worst of all, there might not be enough medicine to help everyone who gets sick.

The following diseases aren’t really an issue in developed countries, but after the SHTF they will be much more prevalent. Learn the symptoms so you can take immediate action.

1. Dysentery – This is an umbrella term that refers to the symptoms of a bacterial infection or parasite in the intestines. Bloody diarrhea, abdominal cramps, weight loss and fever are the most common symptoms. Dysentery occurs when water is not cleaned before consuming. It can also be caused by improperly cooked food, too.

2. Cholera – This disease has been wiped out in the United States, but it would make a comeback if sanitation system went down. It’s caused by the bacteria Vibrio cholerae. The symptims include water diarrhea, which quickly leads to dehydration. It is spread by feces contaminated water supplies. Flood waters can distribute Cholera throughout an entire region. Muscle cramps, a rapid heart rate and low blood pressure are also common symptoms of Cholera.

3. Hepatitis A – Hepatitis A is a virus that can be contracted via contaminated food or water supply. If a person infected with the virus uses the bathroom, doesn’t wash their hands thoroughly and then prepares food for someone else, the virus can be spread. Even touching another person who then touches their food could result in picking up the virus. It can also be spread through water that has come in contact with infected stool. Symptoms typically include pain on the right side, tiredness, loss of appetite and most obvious, jaundice. Yellowing of the skin and whites of the eyes are good indicators.

4. Tuberculosis – This is a dangerous bacterial infection that imitates many other illnesses, which can make it tough to diagnose. Most people who are exposed to TB will not develop symptoms. However, if the immune system weakens, say from another illness caused by lack of sanitation, the TB would likely become active. Anybody with active TB symptoms is contagious. TB typically attacks the lungs. A person with TB who coughs or sneezes can spread TB via the air. Symptoms usually include a cough, chest pain and sputum laced with blood. Weakness and loss of appetite are also common signs.

5. Typhoid Fever – Typhoid is a bacteria that is spread via contact with human feces of an infected person. It is an extremely serious condition that can be fatal. The key symptom is a high fever and a rash, although not every person will develop the rash. It can take a week before symptoms appear. Water that has been contaminated with human feces that contains the bacteria is a common source of transmission.

6. West Nile Virus – While it is rare in the U.S., there have been cases of this virus spread via mosquito bites. When sanitation systems are down and there are pools of stagnant water, there will be more mosquitoes. Without proper ventilation, the bugs will be atrocious. Mosquitoes pick up the virus when they dine on infected birds and then pass it to humans. Symptoms mimic the flu and in very few cases is it fatal. The elderly and very young are more likely to have a severe response to the virus.

7. Leptospirosis – This is a bacteria that can afflict humans and animals and causes intestinal issues. Imagine the amount of displaced animals after a disaster. Humans and animals would be sharing water sources, which could lead to a massive outbreak. Leptospiriosis is generally not fatal to humans, but in some, it can lead to secondary illnesses like meningitis and kidney failure. Symptoms tend to look like the flu, which can make diagnosis without modern technology a problem.

8. Meningitis – Meningitis can be viral, which is a huge risk, especially in areas where there are large groups of people sharing the same resources, including air. Although viral meningitis is spread easily, it is less serious than bacterial meningitis. A stiff neck, lack of appetite, headache, nausea and sensitivity to light are all common symptoms. Bacterial meningitis can be contracted via the flu virus.

After a major disaster or other event that upsets the world as we know it, diseases that have been eradicated in the United States are very likely to appear again. Poor sanitation, dead bodies and flooding will lend to an unsafe environment, riddled with disease. There are a number of respiratory and intestinal diseases that appear in today’s world, like the Norovirus or E. coli, but they are rare cases. We don’t give a lot of thought to them because we know we have modern medicine to treat the symptoms.

Disaster will have people desperate for basic supplies like food and water. Water that is contaminated will be everywhere. Medical facilities will not have access to the medicines and disinfectants they have today. Survivors will likely congregate in shelters where a single virus can spread like wildfire in a matter of days due to the confined space and limited sanitation. This is yet another reason you need to be prepared, so you don’t have to join the masses where disease could be everywhere.